Mailbox migration fails after Extended Protection is enabled

Symptoms 

Consider the following scenario: 

• You install Microsoft Exchange Server 2019 Cumulative Update 12.

• You enable Extended Protection by running the Exchange Server Extended Protection script.

• You configure the Hybrid agent from the Exchange Control Panel (ECP).

• You try to migrate any Microsoft Exchange 2019 mailbox from On-Premises to Online.

In this scenario, mailbox migration fails after you enable Extended Protection.

Resolution 

To fix this issue, install Cumulative Update 13 or a later cumulative update for Exchange Server 2019.